Absorption refrigeration



Patented May 19, 1936 UNITED STATES PATENT OFFICE ansoar'non nsnmnna'non Glenn F. zellhoefer, Blnomington, 11!.

No Drawing. A

ml! Serlai No. 19,595

may 3, 1935,

2 Claims. (Cl. 25H) ed to be evaporated or boiled as a vapor from the solvent mixture and from the solvent, and adapted to be condensed from the the vapor to a liquid.

Numerous refrigerants and numerous solvents are grown, as well as successful combinations of ese.

The two-fluid absorption machines have certain mechanical parts which may be omitted or which are not duplicated in three-fluid machines. In a. three-fluid machine, there is, in addition to the two-fluid mixture, a body of inert gas which is always gas, and which does not to any substantial extent dissolve in any of the components of the two-fluid composition, or in mixtures thereof.

The present invention is directed to a new solvent for absorption refrigeration, and to combinations thereof with refrigerant s.

A particular object of the invention is the use of monomethyl ether of diethylene glycol acetate as a solvent.

Another object is the use of a combination of said solvent with the refrigerant dichloromonofluoromethane.

Examples of the two-fluid apparatus in which the new solvent material and the new combination may be used is disclosed in my co-pending application Serial No. 651,306, filed January 12, 1933, or in my U. S. Patent No. 1,895,698, issued January 31, 1933. Other examples may readily be cited, and will be known to those skilled in the art.

The two-fluid apparatus above referred to,brlefly described, comprises a still in which a liquid mixture of solvent and refrigerant is heated to distill away as a vapor the refrigerant material, a condenser wherein said vapor is condensed to a liquid state, an evaporator wherein the resulting liquid is vaporized at reduced pressure to produce refrigeration, and an absorber in which vapor of the refrigerant material containing added heat units (acquired in the refrigerating process) is again dissolved in the solvent material; Suitable heat exchanging and circulating means are included, and automatic controls may be provided.

The particular characteristics of such a machine are that the still operates at temperatures well above normal temperatures, such for example at 210 F. to 250 F.; and that the cooling unit operates at temperatures lower than normal, such as from 15 F. to 50 F. Various parts of the apparatus differ in the prevailing temperatures and pressures, and both pressure and temperature. determine the physical state of the free refrigerant material, whether gaseous or liquid, and determine the solubility relations between the refrigerant and the solvent material. It is, therefore,

very important that the solvent and the refrigerant materials be physically adapted for use as individual materials in certain places andfor certain functions, and that they be mutually adapted for certain functions when they are in combination. Other qualities not essential to refrigeration, but pertinentto practical usage, control or limit the choice of solvent or refigerant, such as odor, viscosity, heat capacity, boiling point,

freezing point, volatility, chemical stability, re- 1 activity, corrosive action, inflammability, toxicity, etc.

By considering the limitations herein set forth and suggested, I have been able to utilize monomethyl ether of diethylene glycol acetate w as a solvent for practical usage, in combination with the refrigerant dichloromonofluoromethane, which is little known.

The new solvent is herein named as monomethyl ether of diethylene glycol acetate, ,but it may be characterized by others as methyl carbitol acetate. However, in order to leave no doubt as to its identity, its structural formula is herein given:

CHJOCHzCHaOCHzCHaCOaCHa The refrigerant herein specified is dichloromonoiluoromethane. In order to leave no doubt as to its identity, its structural formula is herein given:

CHClzF In the accompanying claims, the invention is set forth as a combination useful in absorption refrigeration. It is to be understood that a simple adulteration of the new solvent in its pure form,

- either by reason of commercial impurities, or by i of refrigeration apparatus consisting of monomethyl ether of diethylene glycol acetate as the essentially predominant solvent, and dichloromonofluoromethane as a refrigerant.

2. A refrigerant mixture for the absorption type of refrigeration apparatus consisting of monomethyl ether of diethylene glycol acetate as the essentially predominant solvent, and a volatile chemically stable halogenated hydrocarbon refrigerant soluble in said solvent.

GLENN F. ZEILHOEFER. 

